Provided are a semiconductor Field-Effect Transistor (FET) sensor and a method of fabricating the same. The method includes providing a semiconductor substrate, forming a sensor structure having a fin-shaped structure on the semiconductor substrate, injecting ions for electrical ohmic contact into the sensor structure, and depositing a metal electrode on the sensor structure, immobilizing a sensing material to be specifically combined with a target material onto both sidewall surfaces of the fin-shaped structure, and forming a passage on the sensor structure such that the target material passes through the fin-shaped structure.